diff options
Diffstat (limited to 'crypto/hmac.c')
| -rw-r--r-- | crypto/hmac.c | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/crypto/hmac.c b/crypto/hmac.c new file mode 100644 index 000000000000..847df9263e16 --- /dev/null +++ b/crypto/hmac.c @@ -0,0 +1,134 @@ +/* + * Cryptographic API. + * + * HMAC: Keyed-Hashing for Message Authentication (RFC2104). + * + * Copyright (c) 2002 James Morris <jmorris@intercode.com.au> + * + * The HMAC implementation is derived from USAGI. + * Copyright (c) 2002 Kazunori Miyazawa <miyazawa@linux-ipv6.org> / USAGI + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the Free + * Software Foundation; either version 2 of the License, or (at your option) + * any later version. + * + */ +#include <linux/crypto.h> +#include <linux/mm.h> +#include <linux/highmem.h> +#include <linux/slab.h> +#include <asm/scatterlist.h> +#include "internal.h" + +static void hash_key(struct crypto_tfm *tfm, u8 *key, unsigned int keylen) +{ + struct scatterlist tmp; + + tmp.page = virt_to_page(key); + tmp.offset = offset_in_page(key); + tmp.length = keylen; + crypto_digest_digest(tfm, &tmp, 1, key); + +} + +int crypto_alloc_hmac_block(struct crypto_tfm *tfm) +{ + int ret = 0; + + BUG_ON(!crypto_tfm_alg_blocksize(tfm)); + + tfm->crt_digest.dit_hmac_block = kmalloc(crypto_tfm_alg_blocksize(tfm), + GFP_KERNEL); + if (tfm->crt_digest.dit_hmac_block == NULL) + ret = -ENOMEM; + + return ret; + +} + +void crypto_free_hmac_block(struct crypto_tfm *tfm) +{ + if (tfm->crt_digest.dit_hmac_block) + kfree(tfm->crt_digest.dit_hmac_block); +} + +void crypto_hmac_init(struct crypto_tfm *tfm, u8 *key, unsigned int *keylen) +{ + unsigned int i; + struct scatterlist tmp; + char *ipad = tfm->crt_digest.dit_hmac_block; + + if (*keylen > crypto_tfm_alg_blocksize(tfm)) { + hash_key(tfm, key, *keylen); + *keylen = crypto_tfm_alg_digestsize(tfm); + } + + memset(ipad, 0, crypto_tfm_alg_blocksize(tfm)); + memcpy(ipad, key, *keylen); + + for (i = 0; i < crypto_tfm_alg_blocksize(tfm); i++) + ipad[i] ^= 0x36; + + tmp.page = virt_to_page(ipad); + tmp.offset = offset_in_page(ipad); + tmp.length = crypto_tfm_alg_blocksize(tfm); + + crypto_digest_init(tfm); + crypto_digest_update(tfm, &tmp, 1); +} + +void crypto_hmac_update(struct crypto_tfm *tfm, + struct scatterlist *sg, unsigned int nsg) +{ + crypto_digest_update(tfm, sg, nsg); +} + +void crypto_hmac_final(struct crypto_tfm *tfm, u8 *key, + unsigned int *keylen, u8 *out) +{ + unsigned int i; + struct scatterlist tmp; + char *opad = tfm->crt_digest.dit_hmac_block; + + if (*keylen > crypto_tfm_alg_blocksize(tfm)) { + hash_key(tfm, key, *keylen); + *keylen = crypto_tfm_alg_digestsize(tfm); + } + + crypto_digest_final(tfm, out); + + memset(opad, 0, crypto_tfm_alg_blocksize(tfm)); + memcpy(opad, key, *keylen); + + for (i = 0; i < crypto_tfm_alg_blocksize(tfm); i++) + opad[i] ^= 0x5c; + + tmp.page = virt_to_page(opad); + tmp.offset = offset_in_page(opad); + tmp.length = crypto_tfm_alg_blocksize(tfm); + + crypto_digest_init(tfm); + crypto_digest_update(tfm, &tmp, 1); + + tmp.page = virt_to_page(out); + tmp.offset = offset_in_page(out); + tmp.length = crypto_tfm_alg_digestsize(tfm); + + crypto_digest_update(tfm, &tmp, 1); + crypto_digest_final(tfm, out); +} + +void crypto_hmac(struct crypto_tfm *tfm, u8 *key, unsigned int *keylen, + struct scatterlist *sg, unsigned int nsg, u8 *out) +{ + crypto_hmac_init(tfm, key, keylen); + crypto_hmac_update(tfm, sg, nsg); + crypto_hmac_final(tfm, key, keylen, out); +} + +EXPORT_SYMBOL_GPL(crypto_hmac_init); +EXPORT_SYMBOL_GPL(crypto_hmac_update); +EXPORT_SYMBOL_GPL(crypto_hmac_final); +EXPORT_SYMBOL_GPL(crypto_hmac); + |